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Introduction

Datacenter virtualization and SDN delivers significant benefits to service providers, including the ability to scale more cost-effectively, as well as gaining greater flexibility in configuring network topologies to optimize network performance for varying workloads. However, server and application performance can be negatively impacted. LSI Axxia® Enterprise Communication Processors combine high performance processor cores and hardware acceleration that can dramatically increase server and application performance.

Virtualization

Most datacenters use standard servers based on x86 processors that are connected using a high-speed Ethernet network. Virtualization technology is transforming the datacenter by running applications on virtual machines (VM) rather than directly on the underlying hardware. Hypervisors are used to virtualize the underlying hardware platform, allowing multiple operating systems and VMs to run on a single server. This gives service providers maximum utilization and flexibility.

Applications and VMs running on virtualized platforms can be dynamically moved within a datacenter, between datacenters or onto remote servers outside the datacenter. This allows the efficient use of compute, storage and network elements and the rapid provisioning of new services. Network virtualization is achieved using technologies such as generic routing encapsulation (NVGRE), virtual local area networks (VL ANs) and virtual extensible local area networks (VXLANs). While VLAN has a limited scalability beyond 4K, VXLAN can support more than 16 million virtual machines. Network virtualization can be performed on the primary processors in the servers or it can be handled by processors integrated onto the network interface cards (NICs). Offloading network virtualization to a dedicated communications processor reduces the workload on the server processors, increasing both network throughput and application performance.

Software-Defined Networking

Software-Defined Networking (SDN) is a new approach to networking for datacenters and other applications. SDN brings many of the advantages of virtualization to networks by separating network management functions (control plane) from the data switching (data plane), allowing both to run on either physical or virtual hardware. A key feature of SDN is the use of open standards allowing interoperability between elements supplied by different vendors.

The SDN control plane consists of one or more controllers that configure and manage the physical and virtual switches that implement packet forwarding. Virtual switches, such as Open vSwitch in an SDN network, can be run on a range of different hardware platforms including standard servers and NICs.

The OpenFlow protocol is used for communication between the controllers and switches in an SDN network. OpenFlow messages are used to configure the packet routing tables within the physical and virtual switches. Packet forwarding resources can be easily reallocated to meet current traffic demands.

VXLAN and OpenFlow on Axxia Processors

The diagrams below show two options for running VXLAN on a standard x86 server platform. In both options the user application is running in a virtual machine on top of a hypervisor. The implementation on the left shows a standard NIC used for the network interface with VXLAN handled by the hypervisor. VXLAN therefore uses x86 processor cycles, increasing network latency and slowing the performance of user applications.

The implementation on the right shows a NIC based on an LSI Axxia® Enterprise Communication Processor. VXLAN is handled by the Axxia processor, offloading the x86 processor and increasing performance. This approach also reduces system power consumption.

VXLAN diagram​​​​​​

Axxia based NICs can also be used to accelerate Open vSwitch, OpenFlow and network security functions. The chart below shows typical system throughput with OpenFlow encapsulation for VXLAN. The data throughput with no acceleration is increased when a NIC based on the LSI Axxia® Enterprise Communication Processor is used.

Conclusion

Accelerating virtual networks is critical to enabling massive scale datacenter networks and simplifying management. Using communications processors or intelligent network interface cards that integrate processor cores and hardware acceleration can dramatically increase server and application performance by offloading multiple functions including VXLAN, Open vSwitch, OpenFlow and network security. By offloading the critical tasks associated with virtualized networking to the Axxia Communications Processor, network and application performance are increased while reducing power consumption.

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